Electronic thread just 0.1mm thick has been developed that can be embroidered into fabrics, opening up new possibilities and applications for smart clothing.
The technology could lead to shirts that act as antennas for your smartphone, workout clothes that monitor your fitness level, sports equipment that monitors athletes' performance, a bandage that tells your doctor how well the tissue beneath it is healing, or even a flexible fabric cap that senses activity in the brain.
Brain monitoring devices using the ultra-thin circuitry are already under investigation by a team from the ElectroScience Laboratory at Ohio State who hope to make brain implants - commonly used to treat conditions from epilepsy to addiction - more comfortable by eliminating the need for external wiring on the patient's body.
"A revolution is happening in the textile industry," said John Volakis, director of the ElectroScience Laboratory.
"We believe that functional textiles are an enabling technology for communications and sensing and one day even medical applications like imaging and health monitoring."
The prototype ‘e-textiles’ are partly created on a typical tabletop sewing machine which would allow them to be manufactured on a large scale relatively easily using many of the machines that already exist in textile factories.
The sewing machines embroider the thread into fabric automatically based on a pattern loaded via a computer file. The researchers substitute the thread with fine silver metal wires that, once embroidered, feel the same as traditional thread to the touch.
"We started with a technology that is very well known - machine embroidery - and we asked: how can we functionalise embroidered shapes? How do we make them transmit signals at useful frequencies, like for cell phones or health sensors?" Volakis said.
"Now, for the first time, we've achieved the accuracy of printed metal circuit boards, so our new goal is to take advantage of the precision to incorporate receivers and other electronic components."
The shape of the embroidery determines the frequency of operation of the antenna or circuit. For example, a broadband antenna consists of more than half a dozen interlocking geometric shapes, each a little bigger than a fingernail, which form an intricate circle a few inches across.
Each piece of the circle transmits energy at a different frequency, so that they cover a broad spectrum of energies when working together. The malleability of the embroidered circuitry allows it to be adapted for many different uses.
Flexible electronics were also demonstrated earlier this year that can be stretched up to four times their original length for a number of possible uses including artificial skin, body sensors and clothing.